Railroad car hand brake



R. w. BURNETT 2,236,563

RAILROAD CAR HAND BRAKE April 1, 1941.

Filed May 4, 1958 3 Sheets-Sheet 1 INVENTOR Richard W Burneil April 1, 1941. R. w. BURNETT A 2,236,563

RAILROAD CAR HAND BRAKE Filed May 4, 1958 5 Sheets-Sheet 2 INVENTOR ATTORNE s April 1,, 1941. R. w. BURNETT (RAILROAD CAR HAND BRAKE Filed May 4, 1938 3 Sheets-Sheet 3 m v F E INVENTOR Richard W Burneit Patented Apr. 1, 1941 UNITED STATES PATENT @FFIQE RAILROAD CAR HAND BRAKE Richard W. Burnett, Chicago, 111.

Application May 4, 1938, Serial No. 205,969

17 Claims.

This invention relates to a railroad car hand brake r thelike.

One of the objects of this invention is to provide a railroad car hand brake which is simple, sturdy and compact in construction and which is eflicient and durable throughout an extended period of operation. Another object is to provide a brake of the above nature which may be safely used by brakemen to control with a minimum of effort the movement of a freight car, for example. Other objects will be in part apparent and in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the drawings in which are shown several of the various embodiments of my invention,

Figure 1 is a sectional elevation of one form of my brake;

Figure 2 is a sectional elevation along the line 2-2 of Figure 1;

Figure 3 is a fragmentary sectional elevation of a portion of the holding and releasing mechanism of the brake shown in Figures 1 and 2;

Figure 4 is a horizontal section along the line 4-4 of Figure 1;

Figure 5 is a sectional elevation along the line 5-5 of Figure 4;

Figure 6 is a fragmentary sectional elevation of a modified form of the holding and releasing mechanism, certain portions thereof being broken Figure 7 is a fragmentary sectional elevation of another modification of the holding and releasing mechanism; and

Figure 8 is an elevation of a portion of the holding and releasing mechanism.

Similar reference characters refer to similar parts throughout the several views of the drawings.

To attain a better understanding of this invention it might here be noted that many of the known hand brakes used on railroad cars are characterized by various deficiencies which render them inefficient in satisfactorily checking the movement of a railroad car and dangerous to the brakeman in operation. Usually brakes of this character utilize some type of holding and releasing mechanism which acts against braking pressure to hold the brakes as set by the brake man. In some types of holding and releasing mechanisms it is impossible to release the brakes without manipulation of the hand wheel against braking pressure which involves a considerable expenditure of energy by the bralreman and subjects him to risk of injury. Still other types of holding and releasing mechanisms fail properly to hold the winding mechanisms of the brakes in set position with the result that inadvertent brake release often occurs. release gradually the brakes as, for example, when the car is rolled over a hump for classification purposes. Unless provision is made for graduated release of the brakes classification of the cars from a hump entails considerable difficulty and risk of injury to the brakeman as he is unable to control effectively the release of the brakes from their set position.

While hand brakes of this nature should be sturdy and well able to withstand hard usage, it is advantageous that they be compact as the space between connected cars is limited. In achieving compactness of construction, however, difficulties are encountered in providing a winding drum fo'r the chain connected to the brake rigging of ample capacity without reducing the efficiency. of the winding mechanism. Spiral drums and other expedients have been resorted to but with indifferent success because of resulting bulkiness of the brake and power loss through excessive friction. Accordingly, it is another object of this invention to provide a hand brake for a railroad car which obviates the above difficulties in a thoroughly practical and eflicient manner.

With reference to Figure l, a railroad car hand brake generally indicated at It includes a housing comprised of a back plate I l and a front plate I2 (Figure 2) having side walls !3 (Figure 1). Back plate I! is secured to a freight car (not shown) by legs M, front plate 52 being secured to back plate I l by legs l5. The front and back plates, accordingly, house the operating mechanism of the brake which comprises generally holding and releasing mechanism generally indicated at E6 and an operating gear ll (Figure 2) mounted on a stud :8 which carries a hand wheel IS. A combined gear and winding drum generally indicated at 29 is mounted on stud 2| secured in the back and front plates and a chain 22. Thus, upon clockwise rotation of stud 18, as viewed in Figure 1, by hand wheel l9 (Figure 2), gear I! (Figure 1), which meshes with the geared winding drum 28, causes chain 22 to be wound on the winding drum. As chain 22 is connected to the brake rigging (not shown) located beneath At times it is desirable tothe car, the brakes are set as the chain is wound on the drum.

Still referring to Figure 1, holding and releasing mechanism I6 includes a ratchet 23 which is suitably secured to stud or shaft I8 and has formed thereon ratchet teeth 24 which are preferably hook-shaped for a purpose to be set forth hereinafter. As is more clearly shown in Figure 2, the upper portions of back and front plates II and I2 are provided with bearing portions I la and I2a, which journal a trip shaft generally indicated at 25. With reference to Figure 8, trip shaft 25 includes supporting portions 26 and 21 which are journaled in bearings Ila and |2a (Figure 2). Trip shaft 25 (Figure 8) includes a pair of eccentrics 28 and 29 suitably spaced from one another and disposed between supporting portions 26 and 21, and which pivotally carry a pawl generally indicated at 3D in Figures 2, 3 and 4.

Pawl 30 includes an annular portion 3| (Figures 3 and 4) which fits about trip shaft eccentrics 28 and 29 (Figure 4) and an extending ratchet tooth engaging pontion or tooth 32 (Figure 3). Pawl tooth 32 is also preferably hookshaped so as properly to engage with ratchet teeth 24, pawl tooth 32 being suitably reenforced and connected to annular portion 3| by a web 33 and reenforcing sides (see also Figure 2). By reason of the hook-shaped formation of ratchet teeth 24 and pawl tooth 32 counterclockwise rotation of ratchet 23, as viewed in Figure 3, i. e. brake releasing rotation of the ratchet, tends to force the ratchet and pawl into .tight engagement and accordingly inadvertent disengagement therebetween from forces exerted by braking pressure is positively precluded. Similarly, upon clockwise rotation, i. e. brake setting rotation of ratchet 23, ratchet teeth 24 are free to ride over pawl tooth 32 by reason of the sloping connection of the non-hooking surf-aces of the ratchet teeth and pawl tooth.

To effect engagement and disengagement between pawl 30 and ratchet 23 a hand lever 35 (Figure 4) is pivotally mounted on an end 36 of trip shaft 25, being maintained thereon by a lock washer 3'! disposed about a reduced portion.38 of the trip shaft wherein it is held by a knob or the like 39. Hand lever 35 includes a boss 40 (Figure whose surfaces 4| and 42 provide a pair of abutments preferably spaced apart approxia mately 180. These abutments, as viewed in Figure 4, are disposed on either side of a projection 43 formed on and extending from trip shaft portion 21. Accordingly, hand lever 35 is freely rotatable about trip shaft 25 through an are somewhat less .than 180. Thus, as viewed in Figure 5, boss 40 is freely movable clockwise in excess of 90 until abutment surface 4| engages projection 43 at which position hand lever 35 would be in the dotted line position (Figure 6) and overbalanced to the right of its pivotal axis which is coincident with the axis of trip shaft 25. In this position, however, pawl and ratchet 30 and 23 (Figure 1) are still in engagement. Continued clockwise movement of lever 35, as viewed in Figures 4 and 5, however, into the position shown in Figure 3 causes rotation of projection 43 (Figure 5) and accordingly rotation of trip shaft 25. Rotation of trip shaft 25 in turn results in rotation of eccentrics 28 and 29 and this has the elfect of elevating the pivotal axis of pawl 30 (Figure 1) through an arc from position A to position 13. As noted above, however, pawl 30 is pivotally momited on eccentrics 28 and 29 and the mere raising of the pivotal axis of the pawl would alone be ineffective to disengage the pawl from ratchet 23. Accordingly, I provide a projedtion or lug 44 extending downwardly from annular portion 3| of pawl 30 and this lug is positioned to slidably engage a boss 45 formed on side wall I3 of housing front plate l2. By reason of this engagement counterclockwise pivotal move ment of pawl 30 about its axis past the point where lug 44 and boss 45 engage is prevented and accordingly, when the pivotal axis of the pawl is shifted from point A to point B, the pawl is raised bodily to disengage pawl tooth 32 from ratchet .teeth 24.

It may now be seen that by reason of the annular displacement of abutment surfaces 42 and 4| (Figure 5), lost motion in excess of is provided before lever 35 (Figure 4) can effect a release ,of the pawl from the ratchet. This lost motion connection is utilized to advantage in effecting graduated release of the brake. To this end, lever 35 (Figure 4) has a weighted end 46 and when the lever is in the overbalanced position referred to above, weighted end 46 causes movement of lever 35 to the position shown in Figure 3 when the engagement between hooked ratchet and pawl teeth 24 and 32 is slightly relieved. This relief is effected by turning hand wheel I9 (Figure 2) against braking pressure to cause a slight amount of clockwise rotation of ratchet 23 (Figure 3) which, in turn, moves the engaging ratchet tooth 24 away from pawl tooth 32 to permit .the overbalanced lever 35 to fall to the position shown. In the course of so falling ratchet and pawl teeth 24 and 32 are completely disengaged because pawl 30 is translated bodily upwardly away from ratchet 23, being prevented from pivoting about its own axis to remain in engagement with the ratchet by the engagement between lug 44 and boss 45.

While holding and releasing mechanism I6 is organized to provide for graduated release of the brake when desired at certain times, however, it is expedient to effect forced release of the brake, i. e. to relieve braking pressure instantaneously without resorting to movement of lever 35 to the limit of its lost motion and thence manipulating hand wheel I9 (Figure 2) as described. This forced release is effected by direct manipulation of lever 35 from the position shown in Figure 4 to the position shown in Figure 3. Such manipulation is considerably assisted by weighted end 46 of lever 35 as it increases the momentum thereof with the result that the inertia of pawl 35 and the frictional engagement between pawl tooth 32 and one of ratchet teeth 24 is overcome when abutment surface 4| (Figure 5) engages trip shaft projection 43. This forces the trip shaft clockwise, as viewed in Figure 5, and accordingly translates pawl 33 (Figure 1) bodily from its solid to its broken line position.

In many instances it is highly desirable that the braking mechanism include provisions for effecting positive engagement of the holding and releasing mechanism. This is particularly true where the brake has been in extended service and various of the parts have become somewhat worn. To this end, trip shaft 25 includes a lug 41 (Figures 4 and 5) disposed between bearing portion 21 and eccentric 29 and accordingly rotatable with the trip shaft. A coacting abutment 48 (Figures 3 and 5) is formed on and extends from annular portion 3| of pawl 30 in the path of lug 41. It follows that when lug 41 engages abutment 4B in counterclockwise rotation of shaft 25 (Figure 5), pawl 30 is moved counterclockwise positively to force pawl tooth 32 (Figure 1,) into engagement with one of ratchet teeth 24.

It mayrnow be seen, with reference to Figure 3, wherein pawl 30 is shown in its disengaged position, counterclockwise movement of operating lever 35 from its releasing position causes engagement between abutment surface 42 (Fi ure and trip shaft projection 43. Continued counterclockwise rotation of lever 35 (Figure effects counterclockwise rotation of trip shaft 25 and accordingly eccentrics 28 and 29 and lug 41. As the eccentrics rotate, the pivotal axis of pawl 30 is lowered from point B (Figure 1) toward point A, and when lug 41' engages pawl abutment 48 and the pawl is forced positively into engagement with ratchet 23 and is so maintained by weighted end 46. In this position brake release is precluded by reason of the hooked engagement between pawl and ratchet teeth 32 and 24. Ratcheting action between the pawl and ratchet, however, is possible as clockwise movement of the ratchet which results from taking up the brakes by hand wheel I9 (Figure 2) causes pawl 30 (Figure 1) to pivot slightly in clockwise direction and ride over the passing ratchet teeth 24. Because of the weighted end 46 of lever 35, pawl tooth 32 is immediately forced back into engagement with the ratchet after it rides over each passing tooth, thus positively engaging the ratchet to preclude inad vertent brake release.

With reference now to the modification shown in Figure 6, most of the elements of the holding and releasing mechanism are the same as those described hereinabove with reference to Figures 1, 2, 3, 4, 5 and 8. Accordingly, trip shaft 25 is journaled as described and includes all of the portions detailed above. In this modification, however, I employ a modified form of pawl generally indicated at I30 including an annular portion I3I pivotally related to eccentri"s 23 and 23.

Pawl I30 includes a tooth portion I32 connected to annular portion I3I by a web I33 and reenforced by side walls I 34. Web portion I33 has a slot I35 formed therein into which a stud or projection extends from a fixed position on back plate II. Engaging and disengaging operation of pawl I30 is effected in substantially the same manner as that with respect to pawl 30 in Figure l, i. e. upon clockwise movement of hand lever 35 (Figure 6) from its full to its dotted line position, lost motion is taken up between the hand lever and trip shaft 25, eccentrics 28 and 29 are rotated somewhat to move the pivotal axis of pawl I30 to the right from point C. Pivotal movement of pawl I30 about its own axis during its movement from point C, which would result in continued engagement of the pawl with ratchet 23, is prevented by the sliding engagement between stud I36 and surface I35a of slot I35. Continued clockwise movement of lever 35 to its broken line position in Figure 6 results in complete disengagement I of pawl I30 from ratchet 23,, as the pivotal axis of the pawl has been moved to point D and the engaging stud I36 and slot edge I35a have caused complete retraction of the pawl from the ratchet. Positive engagement of the pawl and ratchet results from counterclockwise movement of hand lever 35 from its broken to its full line position in substantially the same-manner as described above with respect to pawl 30 (Figure 1).

With reference to the modification shown in Figure 7, all parts are substantially similar to those shown in Figure 1 with the exception of the engaging projection 44 and boss 45 of Figure 3. Instead of these parts I provide, as shown in Figure '7, an upwardly projecting lug I31 on a pawl generally indicated at I38 which is pivotally mounted on trip shaft eccentrics 28 and 29 as hereinbefore described. Pawl projection I3! slidably engages one side I39 of a projection I49 formed on the top of the brake housing. The engagement between projection I31 and side I39 prevents counterclockwise pivoting of pawl I38 into ratcheting position with ratchet 23 as the pivotal axis of the pawl is moved from point E toward point F upon rotation of eccentrics 28 and 29. When the eccentrics have sufficiently raised the pivotal axis to point F, the pawl is completely disengaged from the ratchet, i. e. it lies in its broken line position and pivotal movement of the pawl from this position toward the ratchet is prevented by engagement between pawl projection I31 and housing side I39.

It is now apparent that the holding and releasing mechanism hereinbefore described is capable of such operation as to effect positive engagement between pawl and ratchet and to effect forced or graduated release therebetween. It further appears that by virtue of the hooked nature of the pawl and ratchet teeth, engagement therebetween is enhanced by forces resulting from braking pressure.

As pointed out above, it is desirable that a hand brake of this nature include winding mechanism by which maximum take-up of the chain attached to the brake-rigging can be attained without, however, winding the chain on itself or enlarging the brake mechanism housing to accommodate an axially extended winding drum or the like. Furthermore, it is important that the diameter of the winding does not exceed a certain maximum as otherwise power losses nullify winding capacity.

To these ends, combined gear and winding drum 20 (Figure 1) comprises a gear 200 inte grally or otherwise connected with a windin drum 20L Preferably winding drum 20I (Figure 2) is integrally formed with the Web of gear 200 and extends axially therefrom to provide a hub portion 202 which is rotatably borne by stud or shaft 2I. Winding drum 20I is provided with a channel 203 which is formed to receive alternate links of chain 22 (Figure 1). Preferably drum 23I is eccentric in form, the eccentricity being designed in accordance with power requisites, and the surfaces of the drum on opposite sides-of channel 203 are provided with bosses 204, 205, 206 and 201 (Figure 1) which support the leading ends of alternate chain links. It will now appear that alternate links 22a, lie in a generally vertical plane and extend into channel 233 whereas alternate links 22b lie in a generally perpendicular plane with respect to the plane of links 22a and accordingly rest against the surface of winding drum 2IlI on opposite sides of channel 203 and against bosses 204, 205, 206 and 201. Furthermore, links 22a all lie in substantially the same plane which precludes the necessity of providing a spiral or helical winding drum and accordingly makes possible a compact structure.

End link 22b (Figure 1) of chain 22 is secured to one end 200a of an anchor member 208 whose other end 2081; is pivotally connected to winding drum 20I by a stud 2539. Preferably the axis of stud 209 is as close as possible to the axis of the winding drum in order to provide a short power arm. Anchor member 208 has a curved inner side' 210 which conforms substantially to hub 202 of drum 20!. The outer side 2l2 of anchor member 208 is preferably formed to receive one of vertical links 22a when a suificient amount of the chain has been wound on the drum. This surface of the anchor member accordingly coacts with winding drum boss 20'! and winding drum channel 203 in forming an extension of the channel to receive added links of chain 22. Accordingly, winding drum 201 may be rotated in excess of 360 and the chain may be wound thereon through such rotation without one conventional chain link engaging any other conventional chain link. In practice, it is possible to attain a drum rotation in excess of 500' without any two portions of the chain interengaging. Thus, by providing anchor member 2I2, the capacity of the winding drum is substantially increased and maximum take-up of the chain and the brake-rigging to which it is attached is accordingly possible without loss of power.

Furthermore, by utilizing anchor member 208 to attach chain 22 to winding drum EM and by utilizing a winding drum of the nature described, the center line of the winding surface for the chain is in a single vertical plane, all of which lends to strength, rigidity and compactness of the brake mechanism and its housing.

For illustrative purposes, the vertical link of chain 22 between supporting bosses S and 20'! is shown out of engagement with anchor member 208. If desired, boss 296 may be disposed nearer the axis of the winding drum, which would permit this chain link to rest against the pivoted end of supporting member 208. This engagement could also result from a variation in the length of chain 22. This, however, would not affect the eificiency of the drum, nor would it give rise to power losses or excessive wear, because anchor member 288 is arranged and particularly adapted to support directly any of the chain links which might engage it. Hence, through the provision of anchor member 288 and its attachment to the drum as close as possible to the axis thereof, winding of the chain in excess of 3E0 is made possible, with the center line of the chain kept sufficiently close to the drum axis that relatively short resistance arms and adequate power are maintained while the chain is wound through a substantially extended are.

It may now be seen that I have provided a hand brake for a railroad car or the like which attains the several objects above set forth in a thoroughly practical and efficient manner.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. Holding and releasing mechanism for a railroad car hand brake comprising, in combination, a housing, a ratchet operatively mounted in said housing, a pawl positioned to engage said ratchet, a trip shaft operatively mounted in said housing, means mounting said pawl on said trip shaft eccentrically to the axis thereof, a hand lever connected to said trip shaft for operation thereof, and means forming a lost motion connection between said trip shaft and said hand lever to effect forced disengagement of said pawl and ratchet when said hand lever is operated in one direction.

2. Holding and releasing mechanism for a railroad car hand brake comprising, in combination, a housing, a ratchet operatively mounted in said housing, a pawl positioned to engage said ratchet, a trip shaft operatively mounted in said housing, means mounting said pawl on said trip shaft eccentrically to the axis thereof, a hand lever connected to said trip shaft for operation thereof, coacting formations on said trip shaft and said means to effect positive engagement of said pawl and ratchet when said hand lever is operated in one direction, and coacting formations on said trip shaft and said hand lever to effect forced disengagement of said pawl and ratchet when said hand lever is operated in one direction.

3. Holding and releasing mechanism for a railroad car hand brake comprising, in combination, a housing, a ratchet operatively mounted in said housing, a pawl pivotally mounted in said housing and adapted to engage said ratchet, means for raising the pivotal axis of said pawl, and means for preventing pivotal ,movement of said pawl in ratchet engaging direction when its pivotal axis is raised whereby disengagement of said pawl and ratchet may be effected, said ratchet and pawl having hook-shaped teeth adapted to hook together and mutually force one another into tight engagement.

4. Holding and releasing mechanism for a railroad car hand brake comprising, in combination, a housing, a ratchet in said housing, a shaft journaled in said housing, an eccentric on said shaft, a pawl pivotally mounted on said eccentric and freely pivotable in relation thereto,

said pawl being adapted to engage or disengage said ratchet as said eccentric is rotated to one position or another, means for moving said pawl bodily through an arc coaxial with said shaft to disengage said pawl from said ratchet, and engageable abutments on said pawl and said shaft adapted to abut during engaging actuation of said pawl and ratchet to effect positive engagement therebetween.

5. Holding and releasing mechanism for a railroad car hand brake comprising, in combination, a housing, a ratchet in said housing, a pawl pivotally mounted in said housing adapted to engage and disengage said ratchet, said pawl having a projection formed thereon, means for moving the pivotal axis of said pawl away from said ratchet, and means adapted to engage said pawl projection during the movement of the axis of said pawl away from said ratchet whereby said pawl is moved bodily from said ratchet and out of engagement therewith.

6. In a railroad car hand brake mechanism having a winding drum connected to a hand wheel and a gear driven by said winding drum, the combination of a ratchet rotatable with said gear, a pawl adapted to engage said ratchet and hold it against braking pressure, eccentric means for disengaging said pawl and ratchet including a trip shaft operatively associated with said pawl through said eccentric, a hand lever for operating said pawl, and means forming a lost motion connection between said lever and said shaf-t whereby operation of said lever through a limited arc has no disengaging effect on said pawl and ratchet, said lever being overbalanced at the end of its lost motion in ratchet releasing direction so that release of braking pressure by operation of said hand wheel results in disengagement of said pawl and ratchet by said overbalanced lever whereby gradual release of braking pressure may be effected by operation of said hand wheel.

'7. In a railroad car hand brake mechanism having a winding drum connected to a hand wheel and a gear driven by said winding drum, the combination of a ratchet rotatable with said gear, a pawl adapted to engage said ratchet and hold it against braking pressure, eccentric means for disengaging said pawl and ratchet including a trip shaft operatively associated with said pawl through said eccentric, a hand lever for operating said shaft, and means forming a lost motion connection between said lever and said shaft whereby operation of said lever through a limited arc has no disengaging effect on said pawl and ratchet, said lever being overbalanced at the end of its lost motion in ratchet releasing direction so that release of braking pressure by operation of said hand wheel results in disengagement of said pawl and ratchet by said overbalanced lever whereby gradual release of braking pressure may be efiected by operation of said hand wheel, said lost motion connection means including cooperating abutments for effecting forced release of said pawl and ratchet against braking pressure upon continued movement of said lever beyond the limit of its lost motion movement.

8. Holding and releasing mechanism for a railroad car hand brake comprising, in combination, a ratchet, a pawl, a shaft, an eccentric mounted on said shaft, said pawl being pivotally mounted on said eccentric, a projection formed on said pawl, a projection formed on said shaft, said projections being adapted to coact to force said pawl into engagement with said ratchet, a lever for operating said shaft, and means forming a lost-motion connection between said lever and said shaft whereby said lever is freely movable through a limited are before effecting rotation of said shaft.

9. Holding and releasing mechanism for a railroad car hand brake comprising, in combination, a housing, a ratchet in said housing, a shaft mounted in said housing, an eccentric on said shaft, a pawl pivotally mounted on said eccentric adapted to engage and disengage said ratchet as said eccentric is rotated, said pawl having a projection formed thereon, the pivotal axis of said pawl moving toward and away from said ratchet as said eccentric is rotated, and means adapted to engage said pawl projection during the movement of the axis of said pawl away from said ratchet, whereby said pawl is moved bodily from said ratchet and out of engagement therewith.

10. Holding and releasing mechanism for a railroad car hand brake comprising, in combination, a housing, a ratchet in said housing, and a pawl pivotally mounted in said housing adapted to engage and disengage said ratchet, said pawl having a projection formed thereon, means for moving the pivotal axis of said pawl away from said ratchet, said projection engaging said housing during the movement of the axis of said pawl away from said ratchet, whereby said pawl is moved bodily from said ratchet and out of engagement therewith.

l1. Holding and releasing mechanism for a railroad car hand brake comprising, in combination, a ratchet, a pawl, an eccentric on which said pawl is revolubly mounted, means for rotating said eccentric, guiding means cooperating with said eccentric to effect engagement and disengagement of said pawl and ratchet at different positions of said eccentric, a projection formed on said pawl, and a projection formed on said first-mentioned means, said projections being adapted to coact to hold said pawl in engagement with said ratchet.

1'2. Holding and releasing mechanism for a railroad car hand brake comprising, in combination, a ratchet, a pawl member, an eccentric member motat-ably associated with said pawl, a lever for rotating one of said members, guiding means cooperating with said eccentric to effect engagement of said pawl member with and its disengagement from said ratchet at different angular positions of said eccentric member, said ratchet and said pawl having hook-shaped teeth adapted to hook together and mutually force one another into tight engagement, and means forming a lost-motion connection between said lever and one of said members whereby said lever is freely movable through a limited are before effecting rotation of one of said members.

13. Holding and releasing mechanism for railroad car hand brake comprising, in combination, a housing, a ratchet mounted on said housing, a shaft mounted on said housing, a pawl eccentrically mounted on said shaft, rotation of said shaft causing the pivotal axis of said pawl to move toward or away from said ratchet depending upon the direction in which said shaft is rotated, and a projection formed on said pawl engaging said housing preventing said pawl from pivotally moving into engaging relationship with said ratchet as the pivotal axis of said pawl is moved away from said ratchet.

'14. Holding and releasing mechanism for railroad car hand brake comprising, in combination, a housing, a ratchet mounted on said housing, a pawl pivotally mounted on said housing, means for moving the pivotal axis of said pawl toward and away from said ratchet, and a projection formed on said .pawl engaging said housing whereby, when .the pivotal axis of said pawl is moved away from said ratchet, the engagement of said projection and said housing prevents said pawl from pivotally moving into a ratchet-engaging position.

15. Holding and releasing mechanism for railroad car hand brake comprising, in combination, a housing, a ratchet mounted on said housing, a pawl, an eccentric upon which said pawl is revolubly mounted, means for rotating said eccentric, guiding means formed on said housing and cooperating with a portion of said pawl to move said pawl into and out of engaging relationship with said ratchet as the angular position of said eccentric is varied, and a lost motion connection between said first mentioned means and said eccentric.

16. Holding and releasing mechanism for railroad car hand brake comprising, in combination, a housing, a ratchet operatively mounted on said housing, a pawl pivotally mounted on said housing and adapted to engage said ratchet, means for raising the pivotal axis of said pawl, and means formed on said pawl engaging said housing for preventing pivotal movement 'of said pawl in a ratchet-engaging direction as its pivotal axis is raised, whereby disengagement and engagement of said pawl and said ratchet may be effected by raising and lowering the pivotal axis of said pawl.

17. Holding and releasing mechanism for railroad car hand brake comprising, in combination, a housing, a shaft mounted on said housing, a lever for operating said shaft, a ratchet mounted on said housing, a pawl eccentrically mounted on pawl and said ratchet may be effected by lawering or raising the pivotal axis of said pawl, and a lost m-o tion connection between said lever and said shaft.

RICHARD W. BURNETT. 

